Banana bunches at a market. Photo credit: Sandra Calkins

The work of plants

Though plants are indispensable for human survival, their contributions to human existence and history are often underappreciated. To underline some of the contributions of plants to wider environmental and socioeconomic processes, this piece considers the works of plants or, to be more precise, the metabolic work of one especially charismatic laborer—namely, the banana plant.[1] While this food crop is nearly sterile and relies on human labor for its reproduction throughout the world, it has made significant contributions to history and culture in the Great Lakes region, especially in what is today south-central Uganda.

Fruiting banana plant. Photo credit: Sandra Calkins
Fruiting banana plant. Photo credit: Sandra Calkins

Thinking with the banana is generative for several reasons: It draws attention to the imbrication of human and plant metabolisms in the longue durée and highlights the importance of place and environmental connection. Moreover, the banana plant in Uganda is connected to a long-standing ethos of growth—an aspiration of forward movement. In recent decades the East African banana was also targeted by philanthropic and scientific initiatives that promise “better bananas for Africans” by manipulating metabolic process in plants. For these reasons, the story of banana plants provides some glimpses of historically accreted yet still very contemporary understandings of what a healthy metabolism should look like in this part of the world.

To contextualize current thinking about metabolism in Uganda, I first discuss the “better bananas” scientific project that has spanned the past decades, and which uses the metabolic work of bananas to deliver health to humans. I situate this effort within a colonial history that promoted ideas of nutritional deficiency in the population in general, and in Ugandan bananas in particular. At the same time, however, both colonial nutrition and the scientific project don’t account for other ways in which bananas have long contributed to human thriving in this part of the world. Thus, at a time of heightened anxiety about the environmental impacts of capitalism and modern development thinking, attending to histories of metabolic thinking in places, such as Uganda, can draw out other ways in which possible futures between people, plants, and the environment can be imagined. While there are clear limitations of metabolic thinking in science, it can still contribute to more ecological forms of thought.

In 2004 an Australian scientist submitted a research proposal that would be consequential for East Africa. After this scientist gained funding from the Gates Foundation, his team set out to create micronutrient-enriched super bananas for Ugandans and East Africans more generally. This project, an Australian-Ugandan research collaboration, initially targeted iron, vitamin E, and vitamin A, but soon focused only on increasing the vitamin A the bananas could deliver. Vitamin A (VA) entails a group of substances widely understood to be critical for vision and resistance against infectious diseases.[2] VA has a well-researched biochemistry, clinical symptoms of VA deficiency are well-known, and its precursor, beta-carotene, has a rather simple metabolism—or metabolic pathway—both in plants and in humans. This means that scientists could easily tap into and increase the ways in which beta-carotene accumulates in the plants’ fruits, turning them orange or “golden” (see imagine 3).

A sliced “golden banana". Photo credit: Sandra Calkins
A sliced “golden banana”. Photo credit: Sandra Calkins

Ugandan researchers in the “better bananas” project pay meticulous attention to plants. They first grow them on nutrient media in the tissues culture lab, where temperature, humidity, nutrition, and light are controlled. Then they wean young plants off the nutrient media and plant them in soil. Plants that grow strong and have adapted well to soil are planted in the field trial, where scientists observe closely how they respond to environmental cues, i.e., exposure to wind, sun, travelling pests, fungi, viral and bacterial diseases.[3] Being able to produce an attractive bunch of golden bananas and growing in robust ways indicates which plant is an ideal metabolic laborer. But such complex thinking is not extended to human bodies in the same way. As a research project in plant science, it is premised on an idea of human bodies absorbing nutrients in rather mechanical and readily quantifiable ways. Scientific calculations assume that the conversion of beta-carotene is a uniform process in all human bodies, that similar quantities of banana are consumed on a daily basis, and that different bodies not only need similar amounts of VA but also are able to draw analogous quantities from plant carotenoids. This particular calculation of health outcomes that consuming these bananas should one day have on human bodies thus ignores variations among human bodies, the effects of diverse modes of cooking bananas, and new research about the complexities of nutritional absorption.

Importantly, this biotech project builds on the idea that metabolic processes between humans and plants are similar enough that the beta-carotene can move in predictable ways from bananas to humans consuming them. To reach its objective and introduce higher micronutrient levels to Ugandan ecologies of eating and cultivating, the project relies on the metabolic labor of plants—on their growth and reproduction, a form of labor through which the micronutrient VA accumulates before it can circulate in a way that benefits humans. What is interesting about this project is that human metabolism is assumed to be regular, unproblematic and uniform. Metabolic thinking about humans nonetheless extends into plant metabolisms well as the gardens and plantations where these crops are being cultivated. Right now, these transgenics are only grown in greenhouses and trial fields, but the goal is to introduce the “better banana” to small-holder farmers across Uganda, where plants would perform their metabolic labor for a wider swath of the Ugandan populace, boosting their VA levels. Improving human nutrition here is an engineered interspecies endeavor, one that relies on carefully calibrated relations between experimental plants and their wider environment. A micro-intervention at the level of banana genes in a lab thus promises to recalibrate broader relationships of growing and eating, even if this project and its bananas are still waiting for much delayed legislation on biosafety that would legalize cultivating and distributing these transgenics.

The goal of creating a micronutrient-enriched banana is a response to a perceived lack of micronutrients in both diets and environments Uganda. This idea of deficient landscapes and bodies in Uganda is a rather recent one. The first European travelers to Uganda were deeply impressed by the lush green landscapes and the abundance of the plantain gardens;[4] they make no mention of deficiency. A colonial report on nutrition in Uganda echoed this sense of an advantageous environment and found the population to be overall well-fed and appearing healthy.[5] Yet Uganda was the first country on the African continent where studies on vitamin A were carried out, at a time when nutritional research generally focused on the role of protein in diets.[6] Signs of vitamin A deficiency were first observed in 1930-31 by British doctors among Ugandan prisoners, who were fed starchy diets.[7] Subsequent studies in the 1930s identified vitamin A deficiency as a dry season problem in grain-eating communities but not in regions where the banana is the main staple.[8] While the banana wasn’t associated with VA deficiency, its role as weaning food in south-central Ugandan was discussed as a cause of protein deficiency in young children in the 1950s and 1960s.[9] It wasn’t until the 1990s that VA deficiency was identified as a widespread problem in Uganda. Several Demographic Health Surveys indicated that between 30-40 percent of Ugandan children and women between 15 and 49 are VA deficient, though this data is questionable (i.e., this figure declined to 9% in the last survey).[10] Despite such uncertain data, an emerging scientific consensus painted a picture where Ugandan bodies, crops, and the environment were newly suspected to cause nutritional deficiencies and thus in need of repair from the outside. Hence the biofortified banana project, with “better bananas” whose metabolism had changed in order to make humans consuming them better able to metabolize vitamin A.

How does the notion of “a better banana” translate in south-central Uganda? The idea that the banana plant needs improvement is not an intuitive one in this part of the world. There, the fertility of the main agricultural crop—the banana (matooke)—has over centuries been understood as key to human thriving, the literal growth of bodies, families, communities, and polities. The biology of this organism, which is a fecund rhizome that can proliferate new suckers continuously, provided a template through which personal and collective growth was and partially still is imagined.[11] Matooke has been intensively cultivated in Uganda for a long time, dating to sometime between the fourteenth and seventeenth centuries. Unlike wide stretches of pre-colonial Africa, the ancient kingdom of Buganda in today’s south-central Uganda was known for its high degrees of population density, permanent settlement, and centralization. Historians explain this density by referring to the banana and the relative ease through which this crop produces an abundance of food year-round.[12] Because bananas don’t have fixed annual seasons for harvesting and planting, they don’t have to be stored but can always be picked at need. A banana plantation signifies this abundance and the abundant labor of plants. Once established, plantations provide a form of wealth that with proper care can last over generations. Banana plants will just grow and produce fruit, over and over. The banana provides a model of healthy growth—a continuous expansion—that differs starkly from ideas of growth that emerged along with the annual production of crops, such as yam or grains, where growth is typically imagined as a seasonally alternating flourish and decay.

Banana bunches at a market. Photo credit: Sandra Calkins
Banana bunches at a market. Photo credit: Sandra Calkins

Historically, collective flourishing relied on the deeply entangled growth of bananas and human bodies. Banana plants are sterile and can’t reproduce without human assistance through gardening. And formerly humans also couldn’t grow and thrive without bananas: for a young man to move ahead meant having land for a matooke garden to be able to marry, to grow and support many children. Attaining full personhood was imagined to be a thoroughly collective process occurring through membership, patronage, and dependency on one’s environment.[13] Of course, things have changed much since the onset of colonization, and higher education in particular has become a means for social mobility and social identity, but many of these ideas persist and a robust orientation towards growth is evident across many domains of contemporary life in Uganda. Thinking about human-environment relationships from such a perspective, we get a sense of accreted understandings of what a healthy metabolism should look like: Banana-like, it should grow and thrive.[14]

The banana plant is a good entry point to examine the affordances and liabilities of metabolic thinking in Uganda. It is at the heart of a recent scientific intervention that intends to fix or improve metabolic activities in plants and human bodies consuming them. This research promotes a relatively recent notion of the deficiency in Ugandan landscapes. Ugandan researchers I encountered think and speak of metabolism mainly in connection with their scientific work—the work cells do in cultures, the chemical reactions involved in the vitamin A metabolism, or the conversion of substances between human and plants. Still, this scientific effort takes place in a context marked by what may be considered another form of metabolic thinking that emerged historically alongside banana cultivation and still affects how people in Uganda imagine the normal unfolding of a human life in terms of growth and expansion. Even the biomedical framework of biofortification relies on a paradigm in which growth is likewise enabled by the metabolic entanglements of bananas and their human eaters.

While we may question exactly how far the banana remains a main vehicle for imagining flourishing and growth in contemporary Uganda, the banana’s metabolic work continues to generate environmental connections. It does physical metabolic labor by growing and producing fruit that humans eat and then in turn metabolize. Recognizing that banana plants do metabolic labor that enables human existence helps appreciating them as beings that have long played an active part in Great Lakes histories.[15] While I highlighted the fact the banana plant is capacious, always growing and expanding, it is also a cultivated plant that is sterile and cannot reproduce on its own—this applies to all cultivate bananas, not only the transgenic plants. This means that thriving is always a multispecies endeavor reliant on both human gardeners and plants, where both are vulnerable and neither could thrive without the other.

Thinking with long histories of human-plant entanglement in south-central Uganda doesn’t per se prove that metabolism is a useful concept for social science and historical analysis. But attending to old and new forms of metabolic thinking allows drawing together disparate historical threads and gestures at a robust way of envisioning long-standing intimacies with plants. Foregrounding such forms of thinking also points at the parochialism of North Atlantic analytics that still so often center on the human narrowly, without appropriate concern for wider ecological connections that make up the human. And whether we want to call it metabolism or not, there is evidence of a robust normative trajectory in Uganda which prescribes that substances, bodies, plants, and their environments should interact to ensure growth. While talk of growth has often become coterminous with destructive capitalist growth, thinking from Uganda cautions against too quickly dismissing the need to grow. In south-central Uganda growth is still a central motif through which people make sense of their lives and health. Put differently, growth is a sign of a healthy metabolism.

[1] Maan Barua, “Animating capital: Work, commodities, circulation,” Progress in Human Geography 43 (August 2019): 650-69. Sarah Besky, and Alex Blanchette, eds., How Nature Works: Rethinking Labor on a Troubled Planet (Albuquerque: University of New Mexico Press, 2019). Marion Ernwein, Franklin Ginn, and James Palmer, eds., The Work that Plants Do. Life, Labor and the Future of Vegetal Economies (Bielefeld: Transcript, 2020).

[2] Alfred Sommer, and Keith West, Vitamin A Deficiency: Health, Survival, and Vision (Oxford: Oxford University Press, 1996), 150-58.

[3] Sandra Calkins, “Between the Lab and the Field: Plants and the Affective Atmospheres of Southern Science.” Science Technology and Human Values (Online First),

[4] John H. Speke, Journal of the Discovery of the Source of the Nile (London: Blackwood and Sons, 1863). Henry M. Stanley, Through the Dark Continent: or, the sources of the Nile, around the Great Lakes of Equatorial Africa, and down the Livingstone River to the Atlantic Ocean (1889; reprint, New York: Dover Publications, 1988).

[5] Uganda Protectorate Nutrition Committee, 1944-1946, Uganda: review of nutrition, Colonial Office 859, Box 116, Folder 4, The National Archives, Kew.

[6] John Nott, “Malnutrition in a Modernising Economy: The Changing Aetiology and Epidemiology of Malnutrition in an African Kingdom, Buganda c. 1940–73,” Medical History 60 (March 2016): 229–49. Jennifer Tappan, The Riddle of Malnutrition: The Long Arc of Biomedical and Public Health Interventions in Uganda (Athens: Ohio University Press, 2017).

[7] J. P. Mitchell, A report of an inquiry into the health conditions of the central prison of Luzira and Kampala, Prisons: annual report on Uganda prisons for 1931, The Colonial Office 536, Box 175, Folder 14, The National Archives, Kew.

[8] L. J.A. Loewenthal, An Inquiry into Vitamin A Deficiency among the Population of Teso Uganda with Special Reference to School Children, Annals of Tropical Medicine and Parasitology 29 (June 1935): 349–360. M.G. Courcy-Ireland, H. R. Hosking, and L. J. Loewenthal, An Investigation into Health and Agriculture in Teso, Uganda,Nutrition Report no. 1—Teso (Entebbe: Government Printer, 1937), 14.

[9] Nott “Malnutrition in a modernizing economy,” 233; Tappan “The Riddle of Malnturition,” 46, 81.

[10] Sandra Calkins, “Food as medicine: Making ‘better bananas’ in Uganda,” The Sociological Review 69 (May 2021): 560-79.

[11] Aloysius Karugaba, Banana Production in Uganda: An Essential Food and Cash Crop. (Relma: Nairobi, 1999). Sandra Calkins, “Health as growth: Bananas, humanitarian biotech and human-plant histories in Uganda,” Medicine Anthropology Theory 6 (October 2019): 29-53.

[12] David L. Schoenbrun, A Green Place, a Good Place: Agrarian Change, Gender, and Social Identity in the Great Lakes Region to the Fifteenth Century (Portsmouth, NH: Heinemann, 1998), 79-93. Rhiannon Stephens, A History of African Motherhood: The Case of Uganda, 700–1900. (Cambridge: Cambridge University Press, 2013), 66-69.

[13] Semakula Kiwanuka, A History of Buganda. From the Foundation of the Kingdom to 1900 (London: Longman, 1971), 154.

[14] Calkins, “Health as growth”; Sandra Calkins and Tyler Zoanni, “On bundling: the aesthetics of exchange and growth in central Uganda,” Africa 93 (July 2023): 371-92.

[15] David L. Schoenbrun, and Jennifer L. Johnson, “Introduction: Ethnic formation with other-than-human beings“, History in Africa 45 (June 2018): 307-45.

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